Let me tell you, during one of the breaks — two of the
breaks — he went backstage. He was having a
meltdown. First he had this little makeup thing, applying
makeup around his mustache, because he had one of those sweat
mustaches. Then he asked for a full-length mirror. I don't know
why, because the podium goes up to here. Maybe he was making sure
his pants weren't wet. I don't know.

Mike Nudelman/Business Insider

Trump fired back later in the day during a press conference in
which New Jersey Gov. Chris Christie, a former presidential
candidate who has previously railed on Rubio, endorsed the New
York real-estate magnate,

"I'll tell you about backstage," Trump said.

Trump continued:

He's with a pile of makeup putting it on his face, I said Marco,
easy with the makeup, you don't need that much. You know the
story with Marco. I watched Marco with this man [Christie]. Where
Marco, he was right over here I asked him I said are you okay? He
looked like he just came out of a swimming pool. He was a mess.

Trump said Rubio was putting makeup on with a "trowel."

"He's a nervous Nellie," Trump claimed. "I watched him backstage,
he's a mess, the guy's a total mess. I joked recently, could you
imagine Putin sitting there waiting for a meeting, and Rubio
walks in and he's totally drenched? I don't know what it is but I
have never seen a human being sweat like this man sweats."

Trump later thanked Christie for his well-known evisceration of
Rubio earlier this month during a New Hampshire
Republican debate, in which Rubio responded to
Christie's attacks by repeating the same canned line.